It has been strongly desired to enhance throughput and improve receiving quality in wireless communications in recent years. To meet this desire, there has been developed a technology of cooperative communications for transmitting data from a plurality of base station apparatuses to a plurality of mobile station apparatuses. Examples of cooperative communications include a technology of multi-input multi-output (MIMO) and a technology of beam forming.
For cooperative communications, there have been developed technologies of precoding and a vector perturbation technique (VPT). Precoding is a technology for improving receiving quality of a receiver, such as a mobile station apparatus, by causing a transmitter, such as a base station apparatus, to add different phases to a certain transmission signal and transmit the signal from a plurality of antennas, for example. Specifically, precoding is carried out by a transmitter adding different phases to a certain transmission signal and transmitting the signal from a plurality of antennas. The VPT is a technology for performing signal processing on a signal to be transmitted in the case where a transmitter is informed of an interference signal multiplexed on a signal to be received by a receiver in advance. The signal processing reduces influence of the interference signal on the receiver.
The VPT is a technology for reducing, when a transmitter transmits a plurality of signals, interference of the signals in a receiver by the transmitter adding specific deviation to the transmission signals and transmitting the signals.
There has also been developed a conventional technology for eliminating interference in advance by a certain mobile station apparatus feeding back an interference elimination coefficient so as to prevent another receiving station from interfering with the receiving station.    Patent Literature 1: Japanese Laid-open Patent Publication No. 2009-213134    Patent Literature 2: Japanese Laid-open Patent Publication No. 2009-105893    Patent Literature 3: International Publication Pamphlet No. WO 2007/091317    Patent Literature 4: Japanese Laid-open Patent Publication No. 2007-208719    Patent Literature 5: Japanese Laid-open Patent Publication No. 2006-5908    Non Patent Literature 1: H. Harashima and H. Miyakawa, “Matched-transmission technique for channels with intersymbol interference,” IEEE Trans. Commun., vol. 20, pp. 774-780, August 1972.    Non Patent Literature 2: M. Tomlinson, “New automatic equalizer employing modulo arithmetic,” Electron. Lett., pp. 138-139, March 1971.    Non Patent Literature 3: B. M. Hochwald, C. B. Peel, and A. Lee Swindlehurst, “A vector-perturbation technique for near-capacity multiantenna multiuser communication-Part II: perturbation,” IEEE Trans. Commun., vol. 53, pp. 537-544, March 2005.